Rotary internal-combustion engine

ABSTRACT

A rotary internal-combustion engine comprising a housing having a peripheral wall with a cylindrical internal surface and side walls defining a main chamber, and a rotor rotary in one direction in the chamber. The rotor has a series of recesses equally spaced around its periphery defining combustion chambers, each recess having a piston pivotally connected at one end thereof at the trailing end of its respective recess for inward and outward swinging movement of the piston in the recess. The side walls have cam tracks on their inner faces and each piston has cam follower means on its free end engageable with the cam tracks. The cam tracks are so developed and phased as to effect inward and outward swinging movement of each piston upon rotation of the rotor for intake and compression of an air-fuel mixture in the combustion chamber and for exhaust of products of combustion therefrom, and to effect rotation of the rotor upon a power stroke of the piston resulting from the combustion of fuel in the combustion chamber.

United States Patent [191 Statkus Dec. 24, 1974 ROTARY INTERNAL-COMBUSTION [58] Field of Search 123/43 R, 43 C, 44 R, 44 E; 418/176, 233, 262, 264

[5 6] References Cited UNITED STATES PATENTS 1,400,255 12/1921 Anderson 123/43 C 2,121,660 6/1938 Hammers 3,320,936 5/1967 Phalen 3,438,358 4/1969 Porsch 123/43 C Primary Examiner-Clarence R."Gordon Attorney, Agent, or Fi'rm-Koenig, Senniger, Powers and Leavitt [57] ABSTRACT A rotary internal-combustion engine comprising a housing having a peripheral wall with a cylindrical internal surface and side walls defining a main chamber, and a rotor rotary in one direction in the chamber. The rotor has a series of recesses equally spaced around, its periphery defining combustion chambers, each recess having a piston pivotally connected at one end thereof at the trailing end of its respective recess for inward and outward swinging movement of the piston in the recess. The side walls have cam tracks on their inner faces and-each piston has cam follower means on its free end engageable with the cam tracks. The cam tracks are so developed and phased as to effect inward and outward swinging movement of each piston upon rotation of the rotor for intake and compression of an air-fuel mixture in the combustion chamber and for exhaust of products of combustion therefrom, and to effect rotation of the rotor upon a power stroke of the piston resulting from the combustion of fuel in the combustion chamber.

4 Claims, 10 Drawing Figures PATENTEB UEC24I974 'SHEEIlUF-Q FIG. I

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ROTARY INTERNAL-COMBUSTION ENGINE BACKGROUND OF THE INVENTION This invention relates to a rotary combustion engine, or rotary pump and is more particularly concerned with a rotary engine or pump of the swinging piston type.

Generally, four-cycle, spark-ignition, intemalcombustion engines operate on the Otto thermodynamic cycle in which air-fuel mixture is inducted into a combustion chamber, compressed, ignited and expanded to produce work, and then exhausted from the combustion chamber. Most conventional Otto cycle engines are of the reciprocating type utilizing a sliding piston, connecting rod and crank arrangement to transmit the energy of the combustion of fuel into rotary mechanical motion and thus do useful work. Although reciprocating engines are reliable and are in widespread use,'their shortcomings (i.e., a large number of moving parts, their size, and inefficiency) have made other types of prime movers appear attractive. Rotary combustion engines have long been known and are being developed to overcome the disadvantages of the reciprocating internal-combustion engines. Pertinent examples of prior art rotary engines may be found in such U.S. patents as No. 1,400,255 and No. 3,438,358.

In the l950s, Felix Wankel introduced'a rotary combustion engine which again operated on the Otto cycle.

Wankel utilized a multilobe rotor rotary in an epitrochoidal chamber to induct and compress an air-fuel mixture to extract useful work from the combustion of this mixture and to exhaust the products of combustion from the engine (see US. Pat. No. 2,988,065). The Wankel engine has fewer moving parts than conventional reciprocating engines and thus is lighter and promises to be less expensive to manufacture. Moreover, due to the symmetrical design and rotary motion of the Wankel engine, vibration and noise are substantially reduced. It was recently found that the emissions of theWankel engine could readily be cleaned to meet the stringent exhaust emission requirements which are to be imposed on all automobiles sold in the United States in 1975. After many years of research and development, Wankel engines are now appearing on the market in increasing numbers. Like all designs, however, the Wankel has shortcomings, such as its specially shaped and difficult to machine epitrochoidal chamber and planetary gear arrangement for its rotor.

SUMMARY OF THE INVENTION Among the several objects of this invention may be noted the provision of a rotary combustion engine of the swinging piston type which has a relatively high power-to-weight ratio; the provision of such an engine which has relatively few moving parts, with many of these parts being interchangeable; the provision of such an engine which requires little machining during fabrication; the provision of such an engine which has a long service life and is easy to service; and the provision of such an engine in which at least two of its pistons are undergoing a power stroke at any one time, thus resulting in a smooth application of power. Other objects and features of this invention will be in part apparent and in part pointed out hereinafter.

Briefly, a rotary intemal-combustion engine of this invention comprises a housing having a peripheral wall with a cylindrical internal surface and side walls defining a main chamber, and a rotor rotary in one direction in the chamber. The rotor has recesses in its periphery spaced at equal intervals therearound defining combustion chambers, and portions of the rotors between the combustion chambers constitute partitions between the combustion chambers, these partitions being in sealing engagement at their outer periphery with the cylindrical internal surface of the peripheral wall. A plurality of pistons are provided, one for each combustion chamber, and are carried by the rotor, each piston being pivotally connected at one end thereof (its trailing end) to the rotor partition at the trailing end of its respective combusion chamber and extending toward the other end of its respective chamber constituting its leading end. Each piston is-in sliding, sealing engagement at its sides with the side walls and at its other or free end opposite its pivoted end with the trailing end of its respective combustion chamber. Cam follower means on each piston is provided adjacent its free end, at least one of the side walls having cam track means receiving the cam follower means. Each pistonis swingable inwardly for a power stroke and a fuel intake stroke and is swingable outwardly for a compression stroke and an exhaust stroke in the course of rotation of the rotor. The housing has air and fuel intake means, fuel ignition means, and exhaust means at spaced intervals around the main chamber for delivery of air and fuel to each combustion chamber, ignition of the airfuel mixture in each combustion chamber, and exhaust of the products of combustion from each chamber. The cam track means is so developed and phased as to effect inward and outward swinging movement of each piston upon rotation of the rotor for the abovementioned intake and compression of the air-fuel mixture and exhaust of the products of combustion, and to effect rotation of the rotor in the one direction upon a power stroke of the piston resulting from combustion of fuel in the respective combustion chamber. The ignition means is spaced relative to the cam trackmeans so that combustion of the air-fuel mixture is initiated as the free end of each piston moves past the ignition means, thereby to effect efficient combustion of the mixture.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a rotary combustion engine of this invention;

FIG. 2 is a side elevation of the engine;

FIG. 3 is a vertical section of the engine taken on line 3-3 of FIG. 1;

FIG. 4 is a vertical section taken on line 4-4 of FIG; 1;

FIG. 5 is a vertical section taken on line 5-5 of FIG. 2;

FIG. 6 is an enlarged top plan view of a piston of the engine of this invention;

FIG. 7 is a vertical section taken on line 7-7 of FIG. 6;

FIG. 8 is-a vertical section taken on line 8-8 of FIG. 6;

FIG. 9 is a perspective view of a piston seal of this invention; and

FIG. 10 is an enlarged cross sectional view taken on line 10-10 of FIG. 3.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, a rotary internalcombustion engine of this invention, indicated in its entirety at 1, is shown to comprise a housing 3 having a peripheral wall 5 with a cylindrical internal surface 7 therein (see FIG. 3) and side walls or plates 9 defining a main chamber 11. The side plates and the peripheral wall are secured together by means of a plurality of bolts 10. A rotor 13, joumalled in side walls 9, is rotary in one direction (as indicated by the arrow in FIG. 3) within chamber 11. Rotor 13 has recesses in its periphery spaced at equal intervals therearound defining combustion chambers 15. Portions of the rotor, as indicated at 17, constitute partitions between the combustion chambers and are in sealing engagement at their outer ends with the internal surface 7 of the peripheral I wall 5. Rotor 13 also has a plurality of swingable pistons, each being indicated at 19 (there being one piston for each combustion chamber). These pistons are pivotally carried by the rotor with one end 21 of each piston (i.e., its trailing or pivoted end) pivotally connected by means of a pin 23 to a respective rotor partition 17 at the trailing end of its respective combustion chamber and the piston extends toward the other or leading end of its combustion chamber.

As shown in FIG. 6, each piston 19 has seals 25 at its sides in sliding, sealing engagement with the inner surfaces of the side plates 9, and a front seal 27 carried by the leading end of the piston in sliding, sealing engagement with an arcuate surface 29 (see FIG. 3) of its respective combustion chamber 11. As shown in FIGS. 3 and 6, side seals 30 and end seals'31 are provided in the rotor 13 adjacent the trailing end of each piston. Seals 25, 27, 30 and 31 thus effectively sealing the piston relative to the side plates, the peripheral wall, and to the rotor. Seals 25 and 27 are received by grooves in the piston at its respective sides and end and are maintained in sliding, sealing engagement with the side plates or with the rotor by meansof flat springs 33. A typical seal (e.g., a side seal) is shown in FIG. 9 to have an outer sealing surface 35, beveled ends 37 to permit movement of the seal in its respective groove relative to the other adjacent seals (see FIG. 6). Sealing surface 35 is relatively narrow to minimize friction of the seal on its respective side plate surface. Seals 30 and 31 are generally similar to seals 25 and 27 heretofore described and are received by slots in the rotor. Gas slots 39 are provided in the sides of the seal to pemiit gases in combustion chamber 15 to flow behind the seal and to push it outwardly so as to force its sealing surface 35 into sealing engagement with its respective side plate surface.

The engine of this invention operates on a modified Otto thermodynamic cycle and has four movements or strokes of each piston/cycle. Each side plate or wall 9 has a cam track groove generally indicated at 41 formed therein, and each piston 19 has cam' follower means 43 adjacent its free end with the cam follower means being received in the above cam grooves, whereby, as the rotor rotates, each piston is swingable inwardly relative to the rotor about is pivot pin 23 for a power stroke and a fuel intake stroke and is swingable outwardly for a compression stroke and an exhaust stroke.

As shown in FIG. 10, cam groove 41 is a T-groove formed in side walls 9 by flanges 47a, 47b extending inwardly at opposite sides of the groove over the groove, thereby to hold the cam follower means captive in the groove. The groove has inner and outer cam. follower surfaces 49a and 49b, respectively. Cam follower means 43 is shown to comprise a roller 51 on each side of the free end of each piston 19 positioned in groove 41 and rolling on cam follower surfaces 49a, 49b therein. Rollers 51 are joumalled on a pin 53 carried by the outer or free end of the piston, the pin 53 extending out beyond the sides of the piston between flanges 47a, 47b of the cam groove.

As shown in FIG. 3, housing 3 has air and fuel intake means generally indicated at 55, fuel ignition means 57 and exhaust means 59 spaced at predetermined intervals around the main chamber 11 or peripheral wall 5 for respectively delivering air and fuel to each combustion chamber 15, igniting the air-fuel mixture in each combustion chamber, and exhausting the products'of combustion from each combustion chamber. More particularly, the air and fuel intake means 55 is shown to be two inlet ports 61 in peripheral wall 5 on opposite sides of the main chamber from one another. In the engine depicted in the drawings, fuel is mixed with air in a carburetor (not shown) and the resulting air-fuel mixture is then inducted into the combustion chamber via inlet ports 61. It will also be understood that fuel may be injected directly into the combustion chambers by fuel injection means. (not shown) rather than inducted into the engine via the inlet ports. Regardless of the induction system, the fuel and air are introduced into the combustion chambers in proper proportions by air and fuel intake means 55 so that they may be ignited by the ignition means 57. It will be further understood thatwith suitable modifications, the engine of this invention may be operated on a variety of fuels including gasoline, kerosene, diesel fuel and liquified gaseous fuels, such as propane. It will be noted that as the outerends of the rotor'partitions 17 move past the inlet ports 55, they constitute valve means for the combustion chambers. More particularly, as a partition moves past an inlet port, it blocks communication between the combustion chamber 15 immediately ahead of the partition and the inlet port' thereby to enable compression of the air-fuel mixture by the piston in the leading combustion chamber, and it opens communication between the trailing combustion chamber and the inlet port, thereby to permit a fresh charge of air and fuel to be inducted into the combustion chamber. Similarly, exhaust means 59 is constituted by a pair of exhaust ports 63 on opposite sides of the peripheral wall 5. Partitions 17 also haust ports.

Fuel ignition means 57 is shown to comprise two continuously firing spark plugs, each indicated at 65. These spark plugs are threaded into openings in the peripheral wall 5 on the opposite sidesthereof between an in-v take port 61 and an exhaust port 63. It is anticipated that the continuously firing spark plugs may possibly be replaced by glow plugs. I

Rotor 13 is splined on a shaft 67 (see FIG. 3) with the shaft joumalled in bearings 69 (see FIG. 5) carried by side walls 9. It will be understood that one end of the shaft, constituting a drive shaft, may be connected to drive means and the other end of the shaft may be used constitute valve'means for opening and closing the ex-' for driving accessories for the engine, such as an electrical alternator or the like.

In FIG. 4, cam groove 41 is shown to be what may be generally described as a closed track surrounding the longitudinal axis of the shaft 67 and symmetrical about two perpendicular lines in the plane of side wall 9 intersecting at the center of the shaft. The cam groove is so developed and phased as to effect inward and outward swinging movement of each piston 19 upon rotation of rotor 13 for the above-mentioned intake, compression, power and exhaust strokes, and more particularly is so developed and phased as to effect two power strokes of each piston for each revolution of the rotor. The cam groove is shown to have four apogee points, as indicated at A1, A2, A3 and A4, and four perigee points, as indicated at P1, P2, P3 and P4, the apogee and perigee points alternating with one another and being equally angularly spaced from one another around shaft 67 at intervals of about 45 and having smooth transitions therebetween. The shape of the transition portions of the cam groove, the angular intervals between the apogee and perigee points, the radial distance of the apogee and perigee points fromm the center of shaft 67, and the position of the intake ports 61,

I spark plugs 65 and exhaust ports 63 in peripheral wall 5 determine the timing, valving, and compression ratio of the engine. The cam groove may be divided into two substantially identical portions, the first starting at apogee point A1 and extending clockwise (as viewed in FIG. 4) around the cam groove to apogee point A3, and the second portion starting at apogee point A3 and extending clockwise around the groove back to apogee point Al. Each of these cam track portions effect movement of each piston as it rotates one-half revolution with rotor 13 through one cycle including intake stroke (Al to P1), a compression stroke (P1 to'A2), a power stroke (A2 to P2), and an exhaust stroke (P2 to A3). While cam groove 41 appears to be a uniform, closed sinusoidal track, the groove may vary in shape and position from one apogee or perigee point to another. For example, the cam dwell prior to the compression stroke (P1 to A2) may remain relatively flat for several degrees of rotation of the rotor past perigee point P1, and then rise sharply toward apogee point A2 to effect rapid compression of the air-fuel mixture in the combustion chamber. This rapid compression reduces blow-by of the air-fuel mixture past seals 25, 27 and 31 carried by the piston. Also, the apogee points Al and A3 are spaced radially outwardly of shaft 67 a distance somewhat greater than apogee points A2 and A4. Thus, the clearance volume between the pistons 19 and the inner wall surface 7 at apogee points A2 and A4 is essentially eliminated, thereby to insure complete exhaustion of the products of combustion from the combustion chambers 11 as they rotate therepast. Also, because the combustion chambers rotate past the exhaust ports 63, more efficient exhausting can be accomplished by pressurizing the productsof combustion in the combustion chamber early in the exhaust stroke, thus effecting a high pressure, high velocity discharge of the exhaust gases from exhaust ports 63. To accomplish this, the dwell at perigee points P2 and P4 is shortened a few degrees, and the dwell at apogee points Al and A3 is lengthened a few degrees so that the rise of the cam groove is steep and the exhaust gases in the combustion chamber are pressurized early in the exhaust stroke. Also, by varying the distance from the removing side plates 9 and replacing them with side plates having a cam grooves 41 of a different configuration.

As illustrated, engine 1 of this invention is an aircooled engine having cooling fins 71 formed on side walls 9 and fins 73 formed on the peripheral wall 5. It will be understood, however, that the engine of this invention may also be water cooled.

Lubrication for the engine may be provided by a series of internal oil passages (not shown) in rotor 13 for supplying oil to the piston pivot pins 23 and to the cam follower rollers 51 via passages (not shown) in each piston with the oil being centrifugally forced outwardly of the rotor to the pistons. i

It is believed that this invention may significantlyre duce the amount of unburned hydrocarbons in the exhaust. In FIG. 3 it can be seen that as each piston 19 undergoes a power stroke, the entire piston from its free end to its pivoted end moves past a continuously firing spark plug 65. Thus, a constantly energized flame front moves across the combustion chamber as the latter moves by the spark plugs. It will be noted that the flame front need move from the spark plug only a relatively short distance to reach the ends of the combustion chamber and thus contributes to complete combustion of the fuel in the combustion chamber.

Unbumed hydrocarbons from the engine of this invention are furtherprevented by elimination of piston run-away. Under certain conditions of engine temperature and speed and with certain fuel characteristics, conventional reciprocating intemal-combustion engines may experience piston run-away which occurs when the piston moves away from the spark plug faster than the flame front, thus resulting in a relatively high percentage of unburned hydrocarbons in the'exhaust gases. In the engine of the present invention, the shape of cam groove 41 and the pivoting of pistons 19 on pins 23 insures that the pistons do not move at too fast a speed from spark plug 65 to induce piston run-away.

It will also be noted that with two of the pistons undergoing a power stroke at the same time, the power produced by the engine of this invention is smooth and balanced and thus eliminates the need for counter weights or flywheels. Also, it will be noted that the rotary intemal-combustion engine of this invention has only ten major moving parts (i.e., rotor 13, shaft 67 and eight pistons 19 with the pistons being interchangeable). Thus, the engine may readily be tom down by removing the side plates 9 and sliding the rotor from the peripheral wall 5, and may be reassembled in reverse manner. I

Increased power may be obtained by arranging or stacking two or more of the engines, in side-wall-to-j side-wall spaced relation, the engines being rotary in the same direction and interconnecting the output shaft 67 of one engine to the input shaft 67 of the other.

It will be understood that with suitable modification, the engine of this invention may be adapted to operate on the diesel cycle as well as the Otto cycle and two cycle or four cycle operation of the engine may be attained. If the engine of this invention is modified tooperate on the diesel cycle, spark or glow plugs are not required to ignite the fuel because the diesel cycle utilizes compression ignition to initiate combustion of the air-fuel ratio in the combustion chambers.

It will be further understood that with the cam grooves 41 substantially symmetrical and that by rotating the peripheral wall about the axis of shaft 67 and aligning the spark plugs 65 with the appropriate cam track apogees, the cycle of the engine may be reversed. With the cycle reversed, the axial symmetry of the invention permits the rotor to rotate the direction opposite to that shown in FIG. 3. In either case, the power output is essentially the same.

It will be still further understood that the rotary combustion engine of this invention, with suitable minor modifications, may be driven via shaft 67 and operated as a rotary pump.

in view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the'above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A rotary intemal-combustion engine comprising a housing having a peripheral wall with a cylindrical internal surface and side walls defining a main chamber, a rotor rotary in one direction in said chamber, said rotor having multiple of four recesses in its periphery spaced at equal intervals therearound defining combus tion chambers, portions of the rotor between said combustion chambers constituting partitions between said combustion chamber in sealing engagement at their outer periphery with said cylindrical internal surface, a plurality of pistons, one for each combustion chamber, carried by the rotor, each piston being pivotally connected at one end thereof to the rotor partition at the trailing end of the respective combustion chamber and extending toward the other end of the respective chamber constituting its leading end, each piston being in sliding sealing engagement at its sides with said side walls and at its free end opposite its pivoted end with said other end of the respective combustion chamber, cam follower means on each piston adjacent its said free end, at least one of said side walls having cam track means receiving said cam follower means, each piston being swingable inwardly for a power stroke and a fuel intake stroke and being swingable outwardly for a compression stroke and an exhaust stroke in the course of each one-half revolution of the rotor, said housing having air and fuel intake means, fuel ignition means and exhaust means at spaced intervals around said main chamber for delivery of air and fuel to each combustion chamber, ignition of airfuel mixture in each combustion chamber, and exhaust of products of combustion from each combustion chamber during each one-half revolution of the rotor, said cam track means having four apogees spaced at substantially equal angular intervals around said side wall and four corresponding perigees, one between each pair of adjacent apogees,

so as to effect corresponding inward and outward movement of pistons diametrically opposed to one another and to effect two power strokes of each piston for each revolution of the rotor, said ignition means being spaced relative to two of said apogees diametrically opposed to one another so as to initiate combustion of said air-fuel mixture in two diametrically opposed combustion chambers as said free end of the piston of each of said opposed combustion chambers moves past its respective ignition means thereby to substantially simultaneously effect efficient combustion of said mixture in each of said opposed combustion chambers, and to effect the balanced application of power to opposed sides of said rotor.

2. A rotary engine as set forth in claim 1 wherein said cam track means is generally symmetrical about at least one axis.

3. A rotary combustion engine as set forth in claim 2 wherein said rotor has eight combustion recesses and eight pistons, and wherein said engine undergoes sixsaid pistons. 

1. A rotary internal-combustion engine comprising a housing having a peripheral wall with a cylindrical internal surface and side walls defining a main chamber, a rotor rotary in one direction in said chamber, said rotor having multiple of four recesses in its periphery spaced at equal intervals therearound defining combustion chambers, portions of the rotor between said combustion chambers constituting partitions between said combustion chamber in sealing engagement at their outer periphery with said cylindrical internal surface, a plurality of pistons, one for each combustion chamber, carried by the rotor, each piston being pivotally connected at one end thereof to the rotor partition at the trailing end of the respective combustion chamber and extending toward the other end of the respective chamber constituting its leading end, each piston being in sliding sealing engagement at its sides with said side walls and at its free end opposite its pivoted end with said other end of the respective combustion chamber, cam follower means on each piston adjacent its said free end, at least one of said side walls having cam track means receiving said cam follower means, each piston being swingable inwardly for a power stroke and a fuel intake stroke and being swingable outwardly for a compression stroke and an exhaust stroke in the course of each one-half revolution of the rotor, said housing having air and fuel intake means, fuel ignition means and exhaust means at spaced intervals around said main chamber for delivery of air and fuel to each combustion chamber, ignition of air-fuel mixture in each combustion chamber, and exhaust of products of combustion from each combustion chamber during each one-half revolution of the rotor, said cam track means having four apogees spaced at substantially equal angular intervals around said side wall and four corresponding perigees, one between each pair of adjacent apogees, so as to effect corresponding inward and outward movement of pistons diametrically opposed to one another and to effect two power strokes of each piston for each revolution of the rotor, said ignition means being spaced relative to two of said apogees diametrically opposed to one another so as to initiate combustion of said air-fuel mixture in two diametrically opposed combustion chambers as said free end of the piston of each of said opposed combustion chambers moves past its respective ignition means thereby to substantially simultaneously effect efficient combustion of said mixture in each of said opposed combustion chambers, and to effect the balanced application of power to opposed sides of said rotor.
 2. A rotary engine as set forth in claim 1 wherein said cam track means is generally symmetrical about at least one axis.
 3. A rotary combustion engine as set forth in claim 2 wherein said rotor has eight combustion recesses and eight pistons, and wherein said engine undergoes sixteen power strokes per revolution of the rotor.
 4. A rotary engine as set forth in claim 1 wherein each of said pistons carries means for sealing said piston relative to the side walls of said housing and to the ends of its respective combustion chamber, said sealing means substantially preventing leakage of said air-fuel mixture and/or said products of combustion therepast and permitting rotation of said rotor and swinging of said pistons. 